Conventional load-based control of engines involves controlling a throttle valve upstream from an intake manifold. During low-load operation, the throttle valve closes to maintain engine speed, which results in decreased intake manifold absolute pressure (MAP). Operating the engine with this decreased MAP, however, results in a penalty where the working pistons are creating vacuum during their intake strokes. This is also known as “pumping work” or “pumping losses,” which decreases fuel economy. Accordingly, while such engines work well for their intended purpose, there remains a need for improvement in the relevant art.